This is all excellent advice. I do expect that some percentage of schools will have e-book options this fall, and a much larger percentage will in the fall of 2013.
You could ask your school contacts point blank which of your courses will have e-book options this fall. They may not know at this point; students that ask may help them move in that direction. Keep asking, and make your decision as late as possible. Deferring decisions is part of the art of engineering. 🙂
At the same time, there's not a huge downside waiting a year in getting an iPad. Performance will be better next year -- especially if processor circuit size shrinks.